Variable area turbine nozzle



Nov. 8, 1966 J. W. TUMAVICUS 3,284,048

VARIABLE AREA TURBINE NozzLE Filed April 28, 1964 4 sheets-sheet 1 NOV 8, 1966 J. w. 'ruMAvzcUs VARIABLE AREA TURBINE NOZZLE 4 Sheets-Sheet 2 Filed April 28, 1964 NOV. 8, 1966 J. w. TUMAvxcus VARIABLE AREA TURB-INE NOZZLE 4 Sheets-Sheet 5 Filed April 28, 1964 .J a y m@ E y N E VM m WWMW M w U MJ Y 5 www Mmm Nov. 8, 1966 J. w. TUMAvlcUs 3,284,048

VARIABLE AREA TURBINE NozzLE u Filed April 2s, 1964 4 sheets-sheet A United States Patent O 3,284,048 VARIABLE AREA TURBINE NOZZLE Julius W. Tumavicus, Indian Town, Old Saybrook, Conn., assigner to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed Apr. 28, 1964, Ser. No. 363,685 15 Claims. (Cl. 253-78) This invention relates to a Variable area inlet nozzle ring for a ygas turbine.

Adjustment of the nozzle area defined between adjacent nozzle vanes has been -generally accomplished by angularly adjusting each vane a'b-out a radial axis passing through the vane. Such adjustment results in large changes in nozzle area with very small changes in angular adjustment of the vanes making accurate control of the nozzle area diicult. One feature of the invention is an arrangement for adjusting the nozzle area by moving each vane about an axis making an angle substantially less than a 90 angle with the turbine axis. Another feature is the support of the opposite ends of the vanes such that the effective adjusting movement -is obtained by relative angular turn-ing movement between the inner and outer vane supporting structures.

More specifically, one feature of the invention is the mounting on one end of each vane for movement about an axis mak-ing an acute angle with ythe engine axis. Another feature is the use of spherical seals in contact with the vane shrouds since such seals will be effective independently of the angular position of the vanes in a mounting of this type.

One feature of the invention is an arrangement of the sealing structure such that the vane shrouds have surfaces which are spherical about the point where the axis of rotation for eac'h of the individual vanes intersects the ax-is of the turbine `rotor thus assuring contact with the fixed sealing surfaces which are also spherical about the same point. Another feature is an arrangement by which to cool the interiors of the vanes independently of the position of the vanes.

Other features and advantages will be apparent from `the specitication and claims, and from the accompanying draw-ings which illustrate an embodiment of the invention.

FIG. l is a fragmentary sectional View through a Vane mounting.

FIG. 2 is a sectional view along the line 2 2 of FIG. 1.

FIG. 3 -is a sectional view along the line 3 3 of FIG. 1.

FIG. 4 is a sectional View along the line 4 4 of FIG. 1.

FIG. 5 is a fragmentary sectional view along the line 5 5 of FIG. 4.

FIG. 6 is a view similar to FIG. 1 on a smaller scale in order to show `the structure by which the rotor and the inner ends of t-he vanes are supported in position.

FIG. 7 is a fragmentary sectional view of a seal.

FIG. 8 is a View similar to FIG. 1 showing a modificat-ion.

FIG. 9 is a fragmentary sectional view along the line 9 9 of FIG. 8.

FIG. 10 is a fragmentary sectional view along the line 10 10 of FIG. 8.

FIG. 1l is a fragmentary sectional view along the line 11 11 of FIG. 8.

Referring first to FIG. 1, the .turbine has an outer casing 10 surround-ing the turbine nozzle assembly 12 and the turbine rotor 14. The latter is mounted in a bea-ring 16, FIG. 6, supported from the -outer casing 10 through a cantilevered sleeve 18. The forward end of the sleeve 18 is suported from the diffuser case 20 at Vthe upstream end of the combustion chamber 21. The diffuser case has struts 22 extending across the gas path to make a rigid connection at this point. The diffuser case is bolted 3284,48 Patented Nov. 8, 1966 to the 'burner case 23 which in turn is bolted to the outer tur-bine casing 10. The outer casing supports an outer duct e-lement 24 for directing hot gas under pressure to the turbine nozzle and the sleeve 18 supports inner duct ele-ment 26 forming ythe inner wall of the gas path. The sleeve 18 also carries an inner support ring 28 for the inner ends of the row of nozzle vanes 30. With this construction, the ring 28 is supported concentrically to the outer casing 10 and prevented from turning movement with respect to the outer casing.

The Ivanes 30 are adjustable for the purpose of varying the nozzle area ydefined by the Vanes to maintain optimum turbine eiiciency. This is accomplished by tilting the vanes in a substantially radial lplane at right angles to t-he turbine axis. The turbine blades 32 on the rotor, against which the gas is `directed by the nozzles, are directly downstream of the vanes, as shown.

The inner end of each vane 30 has .a projecting stem 34 on which a ring 36 is held by a clamping nut 38. The ring has a -spherical 4outer surface fitting in a spherical socket 40 positioned in a cylindrical flange 42 and forming a part of the support ring 28. In this way the vane is mounted for pivotal movement about the axis of the spherical surface on the ring 36. At the junction of the stem 34 with the operative air-foil portion 44 of the vane is an inner shroud 46 having a spherical surface 48 on the forward end thereof for engagement with the edge of the sealing ring 50 attached to and extending outwardly from the support ring 28. The vane is shown as hollow and communicates with the lhollow stem 34 through a radial passage 52 in the 4inner shroud.

The outer end of each vane has an outer shroud 54, the forward edge S6 of which is spherical and is in a position to engage with a large diameter sealing ring 58. The latter is supported by a sleeve 60 which in turn is supported on a ring 6-2 to which it is attached as by bolts 64. The ring 62 is an actuator ring mounted for turning movement Within the outer casing 10, being supported by a row of balls 66 enga-ging in grooves in the ring 62 and in a stationary ring 68 bolted to the outer casing. The actuator ring 62 is held in the position shown concentrically Within the outer casing by the balls 66. An annular seal 70 attached to the sleeve 60 projects outwardly into sliding engagement with the outer casing. The ring 62 is held axially in position through a resilient annulus 72 attached to and extending rearwardly from a heat shield 74 attached `to the outer duct wall 24 and having sliding engagement with 'an annular surface 76 on the end of the ring 66. The annulus 72 is arranged in a bellows configuration to provide a measurable resilience to accommodate differential thermal expansions.

The actuator ring 62 has a plurality of circumferentially spaced radial slots 78, one for each vane, arranged at an acute angle to the axis of the ring, with each slot receiving a sleeve 80, FIG. 3, surrounding a pin 82 carried by a projection 84 on the vane shroud 54. As shown, the projection 84 has spaced lianges 86 and 88 receiving opposite ends of the pin 82 and the liange 88 is also engageable with an inwardly extending flange on the actuator ring 62 to aid in locating lthe outer end of the vane. The pin 82 on which the vane pivots when the ring 62 is moved angularly has its axis, the line 92, FIG. 6, extending at an acute angle to the longitudinal turbine axis, the line 93, FIG. 6. The shroud 54 has a port 91 therein for flow of coolant through the vane.

Since the vane has its inner end located by the spherical joint, i-t will move from a radial position shown in full lines in FIG. 2, into the dotted position of this figure such that the vane axis becomes tangent to a small diameter circle. This movement of the vane is a result of the movement of the actuator ring 62 within the outer casing and the extent of movement of the vane is proportional to the extent of movement of the ring 62. The slots 78 in the ring 62 provide for the necessary radial movement of the outer ends of the vanes as the actuator ring 62 is yturned since obviously with the inner end of the vane held against radial movement, the outer end of the vane will have a small radial component of motion.

For moving the actuator ring 62, the latter has a projecting flange 94 thereon connected by a link 96 to an eccentrically positioned stud 98 on the inner end of a radially mounted stub shaft 98 on the inner end of a radially mounted stub shaft 100 extending through and mounted for rotation in the casing 10. Turning of the shaft 100 will exert a circumferential pull on the ring 62 and thereby impart turning movement to this ring. For motion of this ring without binding, a plurality of stub shafts 100 may be provided in circumterentially spaced relation one to another, with these shafts interconnected by a gear 102 mounted on the outside of the casing and meshing with gear teeth i104 on the several shafts. This will assure a more uniformally applied turning force on the ring 62. One or more of the shafts 100 may have a driving spline 106 at its outer end by which to impart rotation thereto.

With this .arrangement it will be apparent that a substantial rotating movement of the stub shafts 100l will be required to impart a relatively small circumferential movement of the actuator ring 62 and in turn a relatively large movement of this rin-g will be required to etect a small'change in the nozzle area.

As the ring 62 is moved circumferentially and the vanes are thus tipped circumferentially, the eect is to rotate the vanes on the axes of the supporting pins 82 to move the opposed surfaces of adjacent vanes toward or away from each other thereby effectively varying the actual area between adjacent vanes. A small change in this area results from a considerable movement of the actuator ring and the change in flow area can therefore be readily and closely controlled.

The seal surface 48 on the inner vane shroud and the seal surface 56 on the outer shroud were described as Spherical. These surfaces are made spherical about a point coinciding with the inter-section of the axes of the pins 82 (the line 92) and the turbine axis (the line 93), the point 107 of FIG. 6. In this way all the surfaces 4S remain substantially within the same spherical surface regardless of the angularity of the vanes. The same is also true of all the surfaces 56.

Referring to FIG. 7, the seal construction for the seal ring S8 is such that there is a freedom for expansion ot the free end of this seal. The seal is a double thickness seal made up of the rin-gs 108 and 110, the latter having a rebent inner edge 112 overlying the ring 108. Each of the rings has spaced slots 114 and 116 to permit expansion and contraction of the two rings adjacent to the rebent edge '112. The slots 114 are staggered with respect to the'slots 116 to minimize leakage. In this Way, the seal will always be in contact with the sealing surface on the vane shroud, as will be apparent. A simil-ar construction is used for the seal 50.

As above pointed out, the hinge pin 82 for each vane extends atan acute angle to the center line of the nozzle.

From experiment, it is believed that the best angle is from 15 to 50. It is apparent that with an angle approximately that shown in the iigures the desired hinge movement of the vanes may occur without an excessive movement of the pin 82 radially within the slot 78 in which it is positioned. The pin 82 is preferably substantially square externally to reduce wear as the pin slides in the slot.

The pivotal axis need not of necessity be in the outer support ring. As shown in FIGS. 8, 9, 10 and ll, the inner support ring 120 for the row of vanes 122 carries the hinge pin 124 and the inner shroud 126 on each vane has projecting lugs 128 and 130 fitting around the pin. The pin 124 has a flange 125 with a spherical surface 132 there-on engaging with a cylindrical seat 134 in -the lug The lug :12S has a slot 136, FIG. l0, therein extending over the pin to provide for radial sliding movement in the slot.

The outer end of each vane 122 has an outer shroud 138 fitting between anges 140 and 142 on a support ring 144. The latter is guided for movement within a surrounding turbine casing 146 and may be moving circumferentially within the casing by a mechanism similar to that shown in FIGS. l to 5. The ring 144 has .a lateral iiange 148 thereon engaging with a part of the casing and a notch 150 in the casing locates the ring axially and radially. To locate the outer shrouds in predetermined circumferential relation to one another, each shroud has a projecting lug 152 therein engaging with a block 154 attached to the support ring. This block engages at opposite ends with two adjacent shrouds 138, as will be apparent. The surfaces 156 and 158 on the shroud 138 are made spherical about a point coinciding with the intersection of the axes of the pins 124 with the turbine axis to assure an appropriate lit as the v-anes are adjusted.

In this arrangement, as the adjusting ring 144 is moved circumferentially each vane pivots on the axis of the supporting pin at its inner end and the vanes are thus moved in a substantially radial plane about the axis of the pins such that the opposed surfaces of adjacent vanes are moved closer together or further apart to reduce or increase the flow area of the nozzle defined between adjacent vanes. n

It is to be understood tha-t the invention is not limited to the specific embodiment herein illustrated and described, but -may be used in other ways without departure from its spiritV as dened by the following claims.

I claim:

1. A Variable area nozzle ring including, inner and outer support rings, vanes extending between said rings and supported thereby, each of said vanes -at one end being hinged individually on the adjacent support ring for movement about an axis making an acute angle with the ring axis, the angles for all of the vanes being substantially equal and means for moving one of said support rings relative -to the other to produce movement of said vanes about the hinge axis.

2. A nozzle ring as in claim 1 in which the other end of each vane is pivotally mounted about a pivot point lying substantially within the support ring.

3. A nozzle ring as in claim 1 in which one of said rings is movable angularly with respect -to the other about the axes of the rings to adjust the angularity of the vanes with respect to radii through the vanes.

4. A nozzle ring as in claim 1 in which the hinge connes-tion includes hinge pins carried by the vane and radial slots in the ring slidably receiving the pin.

5. A nozzle ring as in claim 1 in which a turbine case surrounds the outer ring 4and means are provided for turning the outer ring within the case.

6. In a variable area inlet nozzle tor a compressor or turbine, `an inner rin-g, a concentric outer ring, defining between the rings an annular ow path for gas through the nozzle, and a plurality of nozzle vanes extending between the rings in a substantially radial direction, the spaces ybe-tween adjacent rings forming nozzles, means on one of the rings for supporting each of the vanes on a hinge axis making 'an acute angle with the axis of the rings, means on the other ring for supporting each vane pivotally .about a point substantially within the rin-g and means for moving one of said support rings relative to the other to produce movement of said vanes about the hinge axis.

7. An inlet nozzle as in claim 6 .in which the hinge axis for each vane is in the outer ring.

8. An inlet nozzle as in claim 6 in which means are provided for Imoving one of the rings circumferentially with respect to the other for `adjusting the angularity of the vanes with respect to a radius through each vane.

9. An inlet nozzle as in claim 6 in which a casing surrounds the outer rin-g, and means are provided for moving the outer ring circumferentially within the casing.

10. An inlet nozzle as in claim 6 in which a casing surrounds the `outer ring, and means are provided for moving the -outer ring circumferentially within the casing, the hinge axis for each vane being in the outer ring.

11. A turbine nozzle construction including outer and inner annular supporting structures dening an annular path therebetween and a plurality of vanes extending between the support structures and across the .annular path, means in one of said structures for hingedly supporting each vane for movement on an axis making an acute 1 angle With the nozzle aXis, means in the other structure for supporting each vane pivotally, and means for moving one of said structures angularly with respect to the other for adjusting Ithe vanes.

12. A nozzle construction as in claim 11 in Which the pivotal support is in the inner supporting structure, and means are provided for moving the outer supporting structure.

13. A nozzle construction as in claim 11 in which a turbine casing surrounds and positions the outer supporting structure, the hinge support for the vane is in the outer supporting structure, and means carried by Ithe cas- References Cited by the Examiner UNITED STATES PATENTS 2,728,518 12/ 1955 Wilde e-t a1. 230-116 X 2,947,466 8/ 1960 Busquet 230-114 3,013,771 12/ 1961 Henny 253-78 X FOREIGN PATENTS 486,761 9/ 1952 Canada. 1,297,645 5/ 196-2 France.

MARTIN P. SCHWADRON, Primary Examiner. E. A. POWELL, JR., Assistant Examiner. 

1. A VARIABLE ARE NOZZLE RING INCLIDING, INNER AND OUTER SUPPORT RINGS, VANES EXTENDING BETWEEN SAID RINGS AND SUPPORTED THEREBY, EACH OF SAID VANES AT ONE END BEING HINGED INDIVIDUALLY ON THE ADJACENT SUPPORT RING FOR MOVEMENT ABOUT AN AXIS MAKING AN ACUTE ANGLE WITH THE RING AXIS, THE ANGLES FOR ALL OF THE VANES BEING SUBSTANTIALLY EQUAL AND MEANS FOR MOVING ONE OF SAID SUPPORT RINGS RELATIVE TO THE OTHER TO PRODUCE MOVEMENT OF SAID VANES ABOUT THE HINGE AXIS. 